Tunnel machine having reversible boring head



Jan. 31, 167 N D PlRRlE ET AL 3,301,600

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27, 1963 6 Sheets-Sheet 1 Jan. 31, 1907 N PlRRlE ET AL 3,301,600

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27, 1965 e Sheets-5heet 2 F W ,I "wg g I 035 .31, 1007. PI RE ETAL 3,301,600

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27, 1963 e sheets-'sheet' s Jan. 31, 1967 D PlRRlE ET AL 3,301,600

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27, 1965 v e Sheets-Sheet 4 Jan. 31, 1967 P|RR|E ET AL 3,301,600

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27. 1963' 6 Sheets-Sheet 5 IN VENTIIYS RTToRNE: y .s

TUNNEL MACHINE HAVING REVERSIBLE BORING HEAD Filed June 27, 1963 Jan. 31, 1967 P|RR|E ET AL 6 Sheets-Sheet 6 -/VoW1/M/ fifiRie ET AL.

ATToRMEyS United States Patent I 3 Claims. (Cl. 299-33) The invention relates to tunnel boring machines suitable for boring through clay and like materials and of the kind comprising a shield and a cutting head mounted on the shield for rotation to cut the tunnel facea'nd means foradvancing the shield and the cutting head along the tunnel as tunnelling proceeds.

The present invention provides a tunnel boring machine of the kind described operable to cut in both directions of rotation of the' head.

Preferably the machine has a first hydrostatic system for advancing the shield and a second hydrostatic system for rotating the cutting head. There may be means, operable in response to a predetermined hydrostatic pressure in the secondsystem, to unload the first system and there may also be means, responsive to a predetermined hydrostaticpressure in the-second system, to unload said second system. Preferably the second mentioned predetermined hydrostatic pressure is greater than the first-mentioned pressure. In one embodiment there are, on the cutting head, cutting mem-bers operable on the cutting face and there is aniannular series of inwardly facing buckets around the cutting head immediately behind the cutting head, the buckets being arranged to receive cuttings as they fall from the cutting members and to convey the cuttings upwardly to a discharge station and there to discharge the cuttings downwardly, the annular series of buckets being contained within the shield and-spaced therefrom and there is, on the cutting head, a scraper member or members in the space between the shield and the buckets and operable to scrape cuttings in the said space upwardly to the discharge station.

There may be an aperture in the cutting head adjacent the scraper, or at least one of them, through which scraped cuttings may be discharged downwardly at the discharge station.

Preferably the cutting head has an annular series of inwardly facing buckets which are open to the tunnel face and are operable to collect cuttings from the tunnel face and to convey the cuttings upwardly to a discharge station and there to discharge the cuttings downwardly. The buckets may be each symmetrical as viewed axially of the machine whereby they are operable for each direction of rotation.

It is preferred that-the shield has a conically flared mouth, the head has an outer shield of frusto-conical form portion, in order to reduce skin friction and to preven undercutting the machine so causing it to dip.

A specific construction of a tunnel boring machine ac cording to the invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of the machine,

FIGURE 2 is a sectional elevation'of the machine with parts removed for the sake of clarity,

FIGURE 3 is a sectional plan of the machine,

FIGURE 4 is a'view in the direction 44 in FIG- URE 2,

FIGURE 5 is a sectional view on the line 55 in FIG- URE 2 with parts omitted for clarity,

FIGURE 6 is a view of the cutting head in the direction 6-6 in FIGURE 2,

FIGURE 7 is a part sectional view of the cutting head taken along the line 7- -7 in FIGURE 2 with parts omitted for clarity,

FIGURE 8 is a sectional view on the line 88 in FIG- URE 6,

FIGURE 9 is an enlarged view of part of FIGURE 2 showing details of the cutting head and the shield, and

FIGURES 10 and 11 are schematic diagrams of the hydraulic circuits to the motors and the rams respectively.

The machine comprises a shield 9 and a cutting head 18 mounted in the shield for rotation.

The shield comprises a cylindrical skin plate 10 with a sole plate 11 extending around the lowest 120 of its periphery. There is within the skin plate 10 a reinforcing ring 24 positioned intermediate inthe length of the 'skin plate 10 and the skin plate is reinforced by a plurality of segments 51 and 52 extending in succession around the skin plate on either side of the ring 24.

A frusto-conical member 25 extends forwardly from the ring 24 and there are removable plates 53in the member for access to pipe lines or the like in the space formed between the segments 51 and the member 25.

The forward edges of the skin plate and the segments are tapered to form a cutting edge for the shield.

Mounting plates 54 extend, rearwardly from the ring 24 and are supported at their rear edges by plates 56 extending inwardly from the segments 52. Reaction rollers are mounted for rotation in roller assemblies attached to the mounting plates 54 and the roller assemblies are adjustable axially of the shield.

The ring 24 is reinforced by gusset plates 27 and there is a horizontal beam 12 extending across the shield. There are gusset plates 15 at the ends of the horizontal beam to provide a large bolting area and to reduce the stress concentration. There is also a vertical beam 14 extending between the bottom of the cylinder and the horizontal beam.

to conform with the mouth and an .inner frusto-conical ring spaced inwardly from the shield, the buckets being open at the front and inwardly at the rear and formed by radial vanes between the inner ring and the shield. The machine may be provided with fixed shedder plates on either side of the discharge station which plates lie beneath the inward openings at the rear of the buckets to prevent cuttings being discharged from the buckets before the buckets reach the discharge station in either direction of rotation.

In a further embodiment of the-invention the shield is of greater outer-radius over one portion of the circumference (e.g. bottom one third thereof) than it is over the remainder and the cutting head cuts a tunnel of the greater radius and substantially concentric with the said The shield is moved forwards by hydraulic rams 28 which bear on the ring 24 and the tunnel linng 29 and the rams are driven by hydraulic pumps 38 mounted on a carriage 37 in the tunnel.

A housing30 is formed in the horizontal beam and the housing carries two supports 31 for a fixed shaft 16. Rotatable on the shaft 16 is a hub 17 of the cutting head 18.

The cutting head 18 comprises four beams or spokes 19 radiating from the hub 17 and an outer annulus 22 plate 60 and the plate 61 is supported on the ring bya number of ribs 63 and corresponding spacer plates 64."

The spacer plates 64 divide the annulus into a series of compartments or buckets 32.

There are four openings .65 in the plate 60 as shown in FIGURE 6. Scraper blades are mounted at the sides of the openings to lie parallel to the axis of rotation of the cutting head. In use the scraper blades scrape against the member 25 to remove any cuttings from the space between the annulus 28 and the shield. There may be rubber wiper blades at the ends of the scraper blades.

At the back of the annulus there is a reaction ring 68 attached to the inner ring 62. The reaction ring runs on the reaction rollers 55. The reaction ring and rollers take all the axial thrust of the annulus. There is a succession of pins 69 around the inside of the reaction ring 68 forming a pin wheel 35.

An important feature of the cutting head is that because of its construction it can be dismounted and assembled in situ through the shield. A

The cutting head is driven by four radial piston hydraulic motors 34 mounted on the shield. Pinions (not shown) in their own bearings are driven by flexible drives from the motors and drive the pin wheel 35 formed on the cutting head. The hydraulic motors 34 are driven by pumps 36 also mounted on the carriage 37.

The cutting head is operable to cut a tunnel in either direction of rotation since it has cutters which will cut in either direction of rotation and since the scraper blades can be mounted on either side of the openings 65. The motors 34 are reversible to effect such rotation. One advantage of two-way rotation is, that roll of the machine can easily be corrected.

The shield carries also a collecting hopper 39 and the front end of a belt conveyor 40 onto which the hopper is directed. The rear end of the conveyor is mounted on {the carriage 37. There are shedder plates 49 on either side of the hopper 39 to prevent cuttings falling out of the buckets before reaching the hopper.

,l The carriage carries an oil reservoir 41 for the hydraulic rams and also the electrical control gear 45 for the machine.

The carriage runs on rails 42 at the sides of the tunnel and there is a second set of rails 43 between the carriage rails. Skips 44 run on the rails 43.

' The hydraulic system will now be described.

The hydraulic circuit to the motors 34 which drive the cutting head is shown in FIGURE 10.

The motors 34 are arranged in two pairs, each connected in parallel with a pump 36 driven by an engine 73. Each pump 36 has in its circuit an auxiliary pump 74 driven by an engine 75 to create a back pressure in the circuit. The pumps 36 are so arranged that they cannot be operated until the back pressure has built up to a predetermined value, detected by a pressure switch 76, to prevent cavitation. The back pressure created is about 100 p.s.i.

The pumps 36 supply fluid at a pressure of about 2400 psi. to the motors 34 by means of one-way valves 77 and servo-operated reversing valves 70. The reversing valves 70 each have two positions-to drive the motors in the forward and reverse directions-and the two valves 70 are operated in synchronism -by a manually operated valve 71. The valve 71 is a reversing valve connected to the supply pressure from the pumps 36 and to the valves 70 by means of a circuit shown in chained lines. When the valve 71 is in the position shown in FIGURE the valves 70 are held in the position shown, but when the valve 71 is moved manually to the left the supply of hydraulic pressure to the valves 70 is reversed around the valves 70 outwardly away from one another in FIG* URE 10. This reverses the supply to the motors 34 to reverse the direction of rotation. There is an accumulator 72 in the circuit to the valve 71 so that the valve 70 can be operated when the pumps 36 are inoperative. The fluid returns to the pump 36 by means ofa filter 7,8.

1.,Each pump 36 is fitted with a stall valve which unloads the pump at a predetermined maximum pressure to avoid overloading the cutting head.

....The two pumps 36 are interconnected as shown and 4 there is a detector 79 to detect the pressure in the circuit. The hydraulic circuit to the rams is shown diagrammatically in FIGURE 11. i

The rams 28 are arranged in parallel on two supply lines81, 82. Each ram is double acting and has its own on-otf valve 80. The two supply lines are fed from a main control valve 83 which has three settings, forward, neutral and reverse in the motor circuit. The valve 83 may be servo-operated in a manner similar to the valves 70 controlling the motors 34.

The main control valve 83 is fed from the two pumps 38 in parallel via an unloading valve 84. The pumps are driven by electric motors 90. The unloading valve 84 is controlled by the detector 79 in the fluid circuit of motors 34 in such a manner that if the pressure in the motor circuit exceeds a predetermined safe pressure (e.g. because the rams have been advanced too quickly) the unloading valve 34 is operated to unload the ram circuit. The detector operates to load the ram circuit at a lower pressure of the motor circuit than that required to unload the ram circuit. Further the ram circuit is unloaded by the detector at a lower pressure than that at which the stall valve on the pump 36 operates to unload the pump.

The return feed from the control valve 83 passes to the pumps 38 by means of the reservoir 41.

The operation of the machine will now be described.

The cutting head is adjusted so that the outer cutters 21 make a cut of which the lowest point is level with the sole plate 11. This means that the machine will overcut the diameter of the cylinder 10 thus reducing the skin friction between the cylinder and the tunnel wall but there will be no undercut so that the machine will keep on the same level as it moves forward.

With the cutting head rotating by means of the pumps 36 and the motors 34 the shield and hence the cutting head are advanced slowly forwards by means of the pumps 38 and the rams 28. The carriage 37 advances with the shield.

Cuttings from the tunnel face are directed by the cutting members 20 intothe buckets 32, which carry the cuttings upwardly and deliver them into the hopper 39. From the hopper the cuttings pass onto the conveyor 40 which carries them rearwardly and finally deposits them in the skip 44 waiting below the carriage 37.

When the rams 28 have been fully extended they are retracted while the shield remains still and further segments of the tunnel lining are put in place. The rams now bear on the new lining and the machine moves forward once again.

The tunnel may be lined conveniently by using the tunnel lining machine described in our British patent specification No. 984,217, or by any other conventional method.

One convenient method of operating the machine is to drive the cutting head in opposite directions of rotation for alternate strokes of the rams. This avoids the machine rolling over to one side. 1

The reversing of the rotation of the cutting head is particularly useful to reverse the head out of an obstruction in the tunnel face.

Advantages of the hydraulic system as compared with the usual drives by electric motors are that the power units are remote from the body of the machine, the speed of rotation 'of the cutting head can be varied over a considerable range (from 1 to 6 revolutions per minute) without loss of torque, the simple reversing mechanism, and the stall devices to prevent damage to the machine.-

It is within the scope of the invention to omit the sole plate from the machine, in which case the cutters would still overcut the shield but the machine would be driven through the tunnel in the look-up position (i.e., with An alternative arrangement of the machine also omitting the sole plate is to make the diameter of the cutting end of the shield greater than the diameter of the rest of the shield. In this way skin friction on the rest of the shield is reduced.

We claim:

1. A tunnel boring machine comprising (a) a non-rotatable cylindrical shield with its axis horizontal,

(b) a cutting head,

(c) means to mount the cutting head on the shield for rotation in either direction about the axis of the shield,

(d) driving means to rotate the cutting head in either direction of rotation,

(e) said cutting head having at its periphery an outer annulus of frusto-conical forms, an inner annulus also of frusto-conical form of shorter axial length than the outer annulus and spaced radially inwardly from the outer annulus, the two annuli having their front edges in the same plane, a ring extending radially inwardly from the rear edge of the outer annulus and a plurality of radial vanes extending in planes containing the axis of rotation of the head, each attached to the two annuli and the ring and spaced apart around the annuli to divide the annuli into a plurality of buckets with mouths open towards the tunnel face and discharge openings open radially inward-1y of the head behind the inner annulus,

(if) a plurality of cutting blades mounted on the cutting head, each blade being symmetrical about a plane through the blade containing the axis of rotation of the head whereby each blade is operable to cut in either direction of rotation of the cutting head,

(g) a discharge chute mounted on the shield below the uppermost discharge openings on the head,

(h) shedder plates attached to the shield and extending around the inner annulus of the head on either side of the discharge station to prevent cuttings being discharged before reaching the chute, and

(i) means to convey cuttings rearwardly from the chute.

2. A tunnel boring machine as claimed in claim '1 in which the shield is of greater outer radius over one portion of the circumference than it is over the remainder and the cutting head cuts a tunnel of the greater radius and substantially concentric with the said portion.

3. A tunnel boring machine as claimed in claim 1 having a first hydrostatic system for advancing the shield, a second hydrostatic system for rotating the cutting head, means operable in response to a predetermined hydrostatic pressure in the second system to unload the first system, and means responsive to a predetermined hydrostatic pressure in the second system, to unload said second system, the second mentioned predetermined hydrostatic pressure being greater than the first-mentioned pressure.

References Cited by the Examiner UNITED STATES PATENTS 977,955 12/1910 Karns 299-91 1,689,596 10/1928 Osgood 173-6 2,134,478 10/1938 Hollingsworth 61-85 FOREIGN PATENTS 270,014 5/1927 Great Britain.

ERNEST R. PURSER, Primary Examiner.

CHARLES E. OCONNELL, Examiner. 

1. A TUNNEL BORING MACHINE COMPRISING (A) A NON-ROTATABLE CYLINDRICAL SHIELD WITH ITS AXIS HORIZONTAL, (B) A CUTTING HEAD, (C) MEANS TO MOUNT THE CUTTING HEAD ON THE SHIELD FOR ROTATION IN EITHER DIRECTION ABOUT THE AXIS OF THE SHIELD, (D) DRIVING MEANS TO ROTATE THE CUTTING HEAD IN EITHER DIRECTION OF ROTATION, (E) SAID CUTTING HEAD HAVING AT ITS PERIPHERY AN OUTER ANULUS OF FRUSTO-CONICAL FORMS, AN INNER ANNULUS ALSO OF FRUSTO-CONICAL FORM OF SHORTER AXIAL LENGTH THAN THE OUTER ANNULUS AND SPACED RADIALLY INWARDLY FROM THE OUTER ANNULUS, THE TWO ANNULIHAVING THEIR FRONT EDGES IN THE SAME PLANE, A RING EXTENDING RADIALLY INWARDLY FROM THE REAR EDGE OF THE OUTER ANNULUS AND A PLURALITY OF RADIAL VANES EXTENDING IN PLANES CONTAINING THE AXIS OF ROTATION OF THE HEAD, EACH ATTACHED TO THE TWO ANNULI AND THE RING AND SPACED APART AROUND THE ANNULI TO DIVIDE THE ANNULI INTO A PLURALITY OF BUCKETS WITH MOUTHS OPEN TOWARDS THE TUNNEL FACE AND DISCHARGE OPENINGS OPEN RADIALLY INWARDLY OF THE HEAD BEHIND THE INNER ANNULUS, (F) A PLURALITY OF CUTTING BLADES MOUNTED ON THE CUTTING HEAD, EACH BLADE BEING SYMMETRICAL ABOUT A PLANE THROUGH THE BLADE CONTAINING THE AXIS OF ROTATION OF THE HEAD WHEREBY EACH BLADE IS OPERABLE TO CUT IN EITHER DIRECTION OF ROTATION OF THE CUTTING HEAD, (G) A DISCHARGE CHUTE MOUNTED ON THE SHIELD BELOW THE UPPERMOST DISCHARGE OPENINGS ON THE HEAD, (H) SHEDDER PLATES ATTACHED TO THE SHIELD AND EXTENDING AROUND THE INNER ANNULUS OF THE HEAD ON EITHER SIDE OF THE DISCHARGE STATION TO PREVENT CUTTINGS BEING DISCHARGED BEFORE REACHING THE CHUTE, AND (I) MEANS TO CONVEY CUTTINGS REARWARDLY FROM THE CHUTE. 